I think Doom 2016 was nothing short of a revolution to the genre for single player. We’ve had the same old CoD style rail shooter for more than a decade as the default for FPS, and Doom 2016 was a breath of fresh air into a somewhat stale world for FPS. For the single player it’s easiest the best FPS of the decade, and I’m looking forward to the next one.
I don’t know what you mean - you have to explore a map to find the keys and secrets, health and ammo. Plus you have the leveling up of the weapons and the suit, and the runes. Agreed, there’s a beginning and an end, but I wouldn’t call it rail shooter in the same way that cod is.
That only applies to certain maps, like foundry, argent facility (undestroyed and destroyed) and the first hell map. After that maps more get linear with some tidbits added. Try resource operations, Lazarus labs or argent tower for example once you get to certain parts you cant backtrack so you just keep following the “rail”. Sure the maps are more diverse in their construction than cod, but the same principal is there.